/*
 * Alloy Analyzer
 * Copyright (c) 2002 Massachusetts Institute of Technology
 *
 * The Alloy Analyzer is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * The Alloy Analyzer is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with the Alloy Analyzer; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package alloy.ast;


public class Path extends TreeNode {

    /**
     * index of package ids in child list
     */
    private static final int PACKAGES_INDEX = 0;

    /**
     * cached copy of string for node
     */
    private String _nodeString = null;

    public Path(){
	super(Location.UNKNOWN, new Ids());
    }
    
    public Path(Location location_, Ids packages_) {
	super(location_, packages_);
    }


    public Path(Ids packages_) {
	super(Location.UNKNOWN, packages_);
    }



    //GET AND SET METHODS

    /**
     * gets the package ids of this
     * @return the {@link Ids}
     */
    public Ids getPackages() {
	return (Ids)childAt(PACKAGES_INDEX);
    }

    /** set the Packages of this */
    public void setPackages(Ids newChild_) {
        setChild(PACKAGES_INDEX, newChild_);
	_nodeString = null;
    }

    /** override setChild to make sure _nodeString
	gets nullified properly */
    public void setChild(int index_, Node node_) {
	super.setChild(index_, node_);
	_nodeString = null;
    }

    /**
     * accept an AST visitor
     * @param visitor_ the visitor
     */
    protected void acceptVisitor(ASTVisitor visitor_) {
	visitor_.visit(this);
    }

    /**
     * accept a returning AST visitor
     * @param visitor_ the visitor
     * @return the Object returned by the visitor
     */
    protected Object acceptReturnVisitor(ASTReturnVisitor visitor_) {
	return visitor_.visit(this);
    }

    public boolean equals(Object obj) {
        return ((obj instanceof Path) &&
                (getPackages().equals(((Path)obj).getPackages())));
    }

    public int hashCode() {
        return getPackages().hashCode();
    }

    
    public final String nodeString() {
        if (_nodeString == null) {
	    _nodeString = getPackages().childrenStr("", "/", "");
	}
	return _nodeString;
    }

    public String toString()
    {
        return nodeString();
    }
}
